Normally the Ford and Merc units are very durable. I had a '53 Merc and it wouldn't surrender from my terrible teenage abuse.
A few have converted to standard ******'s but its a very involved project and some parts are now hard to find (i.e. shift column, carb linkage, differential unit).
You can purchase ****** rebuilding kits for them. I understand the current problem is that the pumps are not being manufactured and they are usually hard to find because they have been slowly being bought-up. Its worth browsing the internet re such issues and at least being familiar the status.